Definition: In this task, you are given an input list A comprising of numbers and alphabets. You need to extract and sort the unique alphabets in the list. The alphabets in the input list will only be in lowercase. Return -1 if there is no alphabet in the input list.
Input: ['8871', 'z', 'z', 'c', 'k', 's', 'q', '8327', '4181']

c, k, q, s, z